1,720,966 research outputs found
Growth analysis of sweet chestnut burr in two seasons with differing weather conditions
Full text linkIn Italy, most of the traditional sweet chestnut (Castanea sativa Mill.) orchards are still non-irrigated since they are located in mountain-hill areas with climate conditions that used to be optimal to sustain the vegetative and reproductive growth of this nut tree species. Nowadays, the increase of summer temperatures and the decrease of rainfall (due to climate change) are affecting negatively chestnut physiological performances. The aim of this experiment was to study sweet chestnut burr growth in two seasons, one warm/dry and one mild/rainy (2017 and 2018, respectively). The study was carried out in a traditional rainfed chestnut orchard. The seasonal burr growth was measured weekly from 30 days after full bloom (DAFB) to the beginning of burr valves opening. Air temperature and daily precipitation were measured at a nearby weather station. The results of this study highlighted that chestnut burr growth seems to be affected by seasonal weather conditions. Indeed, in 2017, the high summer temperatures and the moderate rainfall in summer (227 mm) and winter-spring (385 mm) appeared to affect negatively burr absolute growth rate (AGR; 0.31 mm day-1) and consequently final burr size (46.2 mm). The mild and rainy weather conditions that occurred in 2018 (663 and 340 mm of winter-spring and summer precipitation, respectively) positively influenced burr AGR (0.54 mm day-1) and therefore its final size (60.8 mm). These preliminary results suggest that the introduction of irrigation as a common management practice for chestnut orchards may promote their resilience to climate change with a positive effect on their productivity and fruit quality
Sensor-fusion and deep neural networks for autonomous UAV navigation within orchards
No full textWith the increase of population in the world, the demand for quality food is increasing too. In recent years, increasing demand and environmental factors have heavily influenced the agricultural production. Automation and robotics for fruit and vegetable production/monitoring have become the new standard. This paper discusses an autonomous Unmanned Aerial Vehicle (UAV) able to navigate through rows orchard rows. The UAV is comprised of a flight controller (AP stack), a microcontroller for analog reading of different sensors, and an On-Board Computer (OBC). Pictures are taken through a camera and streamed through WiFi to a Ground Control Computer (GCC) running a convolution neural network model. Based on prior training, the model outputs three directions: RIGHT, LEFT and STRAIGHT. A moving average of multiple frames per second is extracted and sent to a build-in Proportional-IntegralDerivative (PID) controller on the UAV. After error correction from this feedback, controller sends the direction to the flight controller using MAVLink protocol's radio channel overrides, thus performing autonomous navigation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Produrre energia in frutteto con coperture fotovoltaiche
No full textIl settore frutticolo è considerato, rispetto alla totalità dei settori agricoli, il meno impattante, ma il suo livello di emissioni è comunque considerevole, con valori che oscillano tra 4,5-10 t/ha di gas serra. Applicando film plastici fotovoltaici è possibile produrre energia e, al contempo, ridurre eccesso luminoso, traspirazione e consumo idrico
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
A plant-based index for plant water status detection and irrigation scheduling in pear 'Abbé Fetel': first results on the use of the IPL index
No full textWater is the most important factor affecting fruit production and quality. Under the threat of climate change, making irrigation effective and efficient is a pivotal issue. This study reports preliminary results on the use of the recently developed, plant-based IPL index for detecting leaf photo-assimilation and scheduling irrigation. This index considers leaf fluorescence variables, RuBisCo activity, leaf and air temperature, which are easy and quick to measure. This rapidity allows a high number of measurements, strengthening the representativeness of data. The trial was carried out on pear 'Abbé Fetel' grafted on quince 'Adam' rootstock and trained as slender spindle. 100 (T100), 50 (T50), 25 (T25) and 0% (T0) of the estimated evapotranspiration were supplied during the whole season. A "Dynamic" (DYN) treatment was added to the static ones, in which water was provided according to the IPL values. When IPL for DYN was lower than that for T100 irrigation was supplied, restoring IPL to values similar to those of T100. Results suggested that IPL was a reliable tool for managing irrigation. DYN reached the same productivity of T100 (45.1 t ha-1, 41 tonnes of which with a diameter >65 mm) but using 56% less water than T100; irrigation water productivity (WPI) was 61 g of fruit fresh matter per liter of water supplied (g L-1) versus 24 g L-1 of T100. Crop water productivity was 13.3 and 9.63 g L-1 in DYN and T100, respectively, when also rain water supply was considered. Although further tests on other species and sites should be performed, these first results suggest that the IPL index could be a promising tool for easy, effective plant stress detection and irrigation schedulin
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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